body,h1,ul{
        margin: 0;
        padding: 0;
    }
    
    ul{
        list-style: none outside none ;
    }
    
    #nav {
        width: 100%; /* 撑开整行 */
        height: 70px;
        background-color: #333;
    }
    
    #nav section {
        width: 1263px;
        height: 70px;
        /* background-color: red; */
        margin: 0 auto;
    }
    
    #nav section h1 {
        width: 240px;
        height: 70px;
        /* background-color: white; */
        background-image: url('./img/logo.png');
        text-indent: -9999px;
        float: left; /* 图片在左 */
    }
    
    #nav > section > ul{
        /* background-color: red; */
        color: #eee;
        height: 70px;
        line-height: 70px; /* 设置height和line-height 文字垂直居中对齐 */
        float: right; /* 导航在右 */
        width: 650px;
    }
    
    #nav > section > ul > li{
        width: 120px;
        text-align: center;
        float: left; /* 导航项在一行 */
    }
    
    #nav > section > ul > li > a{
        color: #eee;
        /* background-color: red; */
        display: block;
    }
    
    #nav > section > ul > li > a:hover,
    #nav > section > ul > li.active a{
        background-color: #000;
    }